In a hybrid electric vehicle having a belted alternator starter (BAS) system, a high-voltage motor generator unit (MGU) is operatively connected to a crankshaft of an internal combustion engine via a belt and pulley. The MGU draws power from a high-voltage battery. Output torque from the MGU is used to crank and start the engine. Such functionality, which is typically provided in both mild and full hybrid powertrain designs, is referred to as engine “autostart”. The ability to selectively turn off the engine during idle conditions is thus referred to as engine “autostop”. The ability to shut off and restart the engine at idle is just one way in which hybrid electric powertrains achieve their superior fuel economy relative to conventional powertrains.